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A NEW METHOD OF COMBATING FUNGUS ON FISHES 
IN CAPTIVITY 

By Paul Zirzow 

J* 

Paper presented before the Fourth International Fishery Congress 
held at Washington. U. S. A., September 22 to 26, 1908 

BULLETIN OF THE BUREAU OF FISHERIES :::::: VOL. XXVIII. P. 937-940 
Documeni No. 693 ::::::::::::::::::::: Issued April, 1910 



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A NEW METHOD OF COMBATING FUNGUS ON FISHES 
IN CAPTIVITY. 

By PAUL ZIRZOW. 
[Translated from the German.] 

Several methods have already been proposed and used for combating 
parasites attacking fishes and for the treatment of diseased fishes. These 
methods consist in the appUcation of baths of dilute watery solutions of 
substances which act as death-dealing agents on the micro-organisms. Greatly 
diluted solutions of salicyl and ammonia have been used for such baths. The 
use of ammonia (i : looo) for this purpose, proposed by Doctor Roth, of Ziirich, 
proved more effective than salicyl, according to experiments made at the 
biological station of Munich, as this agent entirely kills off parasitic worms. 

The treatment of fishes with baths of this kind has, however, the disad- 
vantage that the fishes themselves suffer from the effects, so that the treatment 
can be given only with the greatest precaution and during a short period. In 
order to obtain a complete recovery, repeated baths have been recommended. 
The treatment of fishes, especially those attacked by fungus diseases, is 
necessarily very tedious, since the destruction of fungus growth can not be 
attained so quickly as the extermination of parasitic worms. 

This disadvantage in the length of time required for effectual treatment 
with baths, as well as the injurious effect upon the diseased fish, may be over- 
come by a method which has been used hitherto only in the transportation of 
live fish. The feasibility of this method has been shown by the results of 
several experiments. 

The new method of combating fungus diseases consists in keeping the dis- 
eased fishes in water regenerated by ozone until the disease has disappeared. 
The adequacy of such treatment was demonstrated by an experiment which 
took place in Galatz in October, 1906, during test of a method of keeping fish 
alive by means of water regenerated with ozone. 

This experiment, in which tench, carp, and shad were used, showed that 
injured fishes which had fungus filaments and growths on their wounds when 

939 



940 BUIvIvETiN OF THE BUREAU OF FISHERIES. 

they were placed in the experiment tanks of a special car and treated with 
ozone were gradually recovering as the experiment progressed, and that at the 
end of the 1 1 8 hours of the experiment the fungus growths had disappeared. 

The tench that had been used in the experiment were placed in the 
Danube in a floating inclosure and after some four weeks were again, with some 
carp, loaded into the special car to be carried back to Berlin. Some of the 
tench again showed signs of fungus. The total quantity of fish used for this 
experiment was 725 kilograms of tench, 1,500 kilograms of carp, and a few kilo- 
grams of pike. The saturation of the water was about 50 per cent, there being 
4,500 kilograms of water. The car reached Berlin after a journey of about 
seventy hours, and it was found that on this occasion likewise, in spite of the 
abnormally high saturation of the water, the growth had again disappeared 
on the fishes and the wounds were healing. The fishes were in good condition, 
and were kept in receptacles a long time after being unloaded. 

Experience gleaned during these experiments indicates that in the use of 
ozone for the regeneration of water it is possible to combat the invasion of 
fimgus growth and to cure the fishes attacked by this disease. 

The method may be applied by keeping the water in which the diseased 
fishes have to be held during their disease in constant rotation and by saturat- 
ing it during its motion with ozone generated by dark electric discharges. 



A NEW METHOD OF COMBATING FUNGUS ON FISHES 
IN CAPTIVITY 

By Paul Zirzow 

Paper presented before the Fourth International Fishery Congress 
held at Washington. U. S. A., September 22 to 26, 1908 

BULLETIN OF THE BUREAU OF FISHERIES :::::: VOL. XXVllI. P. 937-940 
Document No. 693 ::::::::::::::::::::: Issued April, 1910 






APR 15 1910 



A NEW METHOD OF COMBATING FUNGUS ON FISHES 
IN CAPTIVITY. 

By PAUL ZIRZOW. 

at 

[Translated from the German.] 

Several methods have already been proposed and used for combating 
parasites attacking fishes and for the treatment of diseased fishes. These 
methods consist in the application of baths of dilute watery solutions of 
substances which act as death-dealing agents on the micro-organisms. Greatly 
diluted solutions of salicyl and ammonia have been used for such baths. The 
use of ammonia (i : looo) for this purpose, proposed by Doctor Roth, of Zurich, 
proved more effective than salicyl, according to experiments made at the 
biological station of Munich, as this agent entirely kills off parasitic worms. 

The treatment of fishes with baths of this kind has, however, the disad- 
vantage that the fishes themselves suffer from the effects, so that the treatment 
can be given only with the greatest precaution and during a short period. In 
order to obtain a complete recovery, repeated baths have been recommended. 
The treatment of fishes, especially those attacked by fungus diseases, is 
necessarily very tedious, since the destruction of fungus growth can not be 
attained so quickly as the extermination of parasitic worms. 

This disadvantage in the length of time required for effectual treatment 
with baths, as well as the injtuious effect upon the diseased fish, may be over- 
come by a method which has been used hitherto only in the transportation of 
live fish. The feasibility of this method has been shown by the results of 
several experiments. 

The new method of combating fimgus diseases consists in keeping the dis- 
eased fishes in water regenerated by ozone until the disease has disappeared. 
The adequacy of such treatment was demonstrated by an experiment which 
took place in Galatz in October, 1906, during test of a method of keeping fish 
alive by means of water regenerated with ozone. 

This experiment, in which tench, carp, and shad were used, showed that 
injured fishes which had fungus filaments and growths on their wounds when 

939 



002 871 235 2 



940 BULLETIN OF THE BUREAU OF FISHERIES. 

they were placed in the experiment tanks of a special car and treated with 
ozone were gradually recovering as the experiment progressed, and that at the 
end of the ii8 hours of the experiment the fungus growths had disappeared. 

The tench that had been used in the experiment were placed in the 
Danube in a floating inclosure and after some four weeks were again, with some 
carp, loaded into the special car to be carried back to Berlin. Some of the 
tench again showed signs of fungus. The total quantity of fish used for this 
experiment was 725 kilograms of tench, 1,500 kilograms of carp, and a few kilo- 
grams of pike. The saturation of the water was about 50 per cent, there being 
4,500 kilograms of water. The car reached Berlin after a journey of about 
seventy hours, and it was found that on this occasion likewise, in spite of the 
abnormally high saturation of the water, the growth had again disappeared 
on the fishes and the wounds were healing. The fishes were in good condition, 
and were kept in receptacles a long time after being unloaded. 

Experience gleaned during these experiments indicates that in the use of 
ozone for the regeneration of water it is possible to combat the invasion of 
fungus growth and to cure the fishes attacked by this disease. 

The method may be applied by keeping the water in which the diseased 
fishes have to be held during their disease in constant rotation and by saturat- 
ing it during its motion with ozone generated by dark electric discharges. 



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